The industry today owes quite a bit to this wonderful little machine. You can read all about the history of the Dreamcast on gaming sites all over like Giant Bomb and GamesRadar. My personal experience tends to echo several of the sentiments of others, albeit with my own spin and personal experiences.
I had initially intended to do a happy birthday Dreamcast post last night, on it's ten year anniversary. I however got entirely too wrapped up in playing some Magic, HALO 3 and CoD 4 multiplayer on XBox Live. In retrospect, I find that to be the most appropriate way to have celebrated the Dreamcast's tenth birthday.
The Sega Dreamcast was the first system to have internet connectivity out of the box. It was only 56kbps to start, but it was there nevertheless. With web browsing capabilities and online gameplay, it was a revolution in the industry that many scoffed at during that particular time. I can still remember playing NFL2k1 over Seganet. The games were competitive, and in some respects, more fun than today. There were no headsets to listen to eight year old kids cuss you out, and apparently "Rage Quitting" had not been invented yet either. Eventually the 56k modem could be replaced by a network adapter. At the time, this was what inspired me to get broadband at home. Literally, I signed up for AT&T @Home due to the Dreamcast. So it begs the question, would the current generation of consoles be where they are today with connectivity, were it not for the Dreamcast? Impossible to answer, but fun to speculate.
It also revolutionized the industry graphically. I don't personally believe we have had as big of a jump graphically since that time. Some of you may not remember how atrocious looking the 32-Bit era actually was. Go and boot up a 3D PS1 or Sega Saturn game if you can. Today the graphics alone can render a good chunk of them unplayable. The jump was as big as the 8-Bit to 16-Bit jump a decade earlier. It was the first time textures were actually smooth and bit-mapped without looking like puke. Every upgrade since has seemed incremental, be it slightly higher resolution textures, bump-mapping, pixel shaders, anti-aliasing, anisotropic filtering or just some good old fashioned polygon pushing horsepower. I'm not saying your 360 or PS3 games look just like a Dreamcast game, but they sure don't look light-years ahead of them like the DC did compared to the 32 and 64-Bit systems of the time.
This was also a system that packed a wallop when it came to software. I still personally proclaim (along with many, many others) that the NFL2k series is still superior to Madden. We finally received Marvel vs. Capcom 2 on XBLA this year, but it's emulation still makes it inferior to the original Dreamcast version from nearly a decade ago. When has a launch title been as impressive as Soul Calibur? It introduced me to the Dead or Alive series with DoA2, and I still have my pre-order calendar believe it or not. SegaGT was the first sim-racer that ever got it hooks into me. Shenmue still haunts my dreams to this day on occasion. I absolutely adore that game. It had the first console MMO in Phantasy Star Online. Speed Devils was a jaw dropper. Sonic Adventure was an abomination, with some good bits thrown in that made it a classic. Ready 2 Rumble was probably considered the graphical showcase at launch due to it's character animation, and was pretty fun to boot.
If there was any one glaring weakness in my eyes, it would be the lack of depth with so many of Sega's own titles. Mostly because Sega was a huge arcade game maker, and so many of their arcade ports were exactly that, shallow arcade games for $50. I still loved every minute of them though, and perhaps that's what made it so special. Every time a big arcade hit came to a home console since the 8-Bit days, we were always promised an "Arcade Perfect" port, yet they never truly were. With the Dreamcast however, that dream was finally realized and sometimes even exceeded.
For those of you that owned one, you know exactly where I'm coming from. For those of you that didn't, to say your missing out on something pretty damn special would be an understatement.
ZDTV Gamespot TV's Dreamcast special:
My personal favorite Dreamcast game Speed Devils in action: